In the new study, Correale and colleagues followed patients with relapsing-remitting MS who had a total of 26 cycles of infertility treatments.

The treatment included drugs that affect the release of hormones that prepare the body for a pregnancy.

Compared to MS patients in remission who did not have the infertility treatments, the women who did had a sevenfold increase in symptom flares and a ninefold increase in enhanced disease activity; this was seen on MRI scans over nine months of follow-up after the last cycle of infertility treatment.

Nearly 3 out of 4 flares (73%) involved new symptoms, and just over 1 in 4 (27%) were considered a worsening of existing symptoms.

The research appears in the latest issue of the journal Annals of Neurology.

Are Patients Who Don’t Get Pregnant Most at Risk?

In a separate study published in mid-June, researchers in France followed 32 women with MS.

In the three months following their infertility procedures, there was a higher rate of MS relapses compared to before the treatments. Women who failed to become pregnant were more likely to relapse than women who became pregnant.

Coetzee says women with MS who are considering assisted reproduction need to know that the treatment may worsen their symptoms.

It is not clear if treatment for infertility affects overall disease progression.

Pregnancy is known to bring on a remission of MS symptoms in many women. Symptoms often worsen after delivery, but giving birth is not believed to affect the long-term progression of the disease.

“The message is not that women with MS should not undergo these treatments,” Coetzee says. “Studies like this are important to help them make informed choices. As MS becomes more and more of a manageable disease, quality-of-life issues like this one are likely to become more of an issue.”